In general, a top part of a vehicle body of an automobile is provided with a roof panel; a plurality of roof rails extending on the lower surface of the roof panel and in the vehicle transverse direction and holding the roof panel; roof side rails joined to the both end portions of the roof rails and extending in the vehicle body front-rear direction of the vehicle body; and pillars, whose upper end portions are joined to the roof side rails, extending downward.
As a conventional structure for a top part of a vehicle body, for example, a roof structure for a vehicle body is known, which is disclosed by Patent Literature 1. In this roof structure of a vehicle body, welded are an outer panel forming a recessed portion in a vertical cross-sectional view by a roof panel; an inner panel joined to the vehicle inner side of the outer panel to form a closed cross-section; a stiffener forming a closed cross-section between the outer panel and the inner panel; and a reinforcing member (a bulkhead portion), whose cross section is substantially U-shaped, joined to the vehicle inner side of the stiffener to form a closed cross-section. Thus, the stiffness of the joint portion between the roof side rails and the roof rails are increased.
This reinforcing member is disposed on the lower side of a recessed portion formed on the roof panel through the opening formed between the substantially U-shaped cross-section of an extending piece and the lower surface of the stiffener. The reinforcing member is welded at one end thereof to the extending piece, and the bulkhead portion of the other end is welded to the inner lower surface of the inner panel.